Using the Fluorescence In Situ Hybridization in the Diagnosis of Trisomy 13 in a Male Newborn From Mali

ABSTRACT

This case report details the first confirmed diagnosis of Trisomy 13 (Patau syndrome) in Mali using Fluorescence In Situ Hybridization (FISH). The male newborn presented with multiple congenital anomalies, including polydactyly and micrognathia. The diagnosis expands the understanding of Trisomy 13 in Africa, highlighting the importance of genetic testing in resource‐limited settings.

Summary.

• This case highlights the critical role of cytogenetic techniques, such as FISH, in diagnosing Trisomy 13 in resource‐limited settings.

• It is the first confirmed case in Mali, expanding the clinical knowledge of this disorder in Africa and underscoring the need for improved prenatal and postnatal genetic screening.

1. Introduction

Trisomy 13, also known as Patau Syndrome, is the third most common autosomal trisomy [1, 2]. It is estimated to affect between 1/10,000 and 20,000 live births and is more prevalent in spontaneous abortions [3]. This chromosomal abnormality is characterized by rich clinical features such as microphthalmia or anophthalmia, cleft lip and/or palate, postaxial polydactyly, ventricular septal defect, holoprosencephaly, omphalocele, and renal dysplasia [2, 4]. The prognosis for infants with Trisomy 13 is poor, with approximately 90% of them dying within the first few days or weeks of their lives, primarily due to severe cardiac and neurological complications [5]. The diagnosis of Trisomy 13 is typically made through prenatal genetic testing such as chorionic villus sampling (CVS) or amniocentesis [6]. Postnatally, it can be confirmed via karyotyping or fluorescence in situ hybridization (FISH) [7]. In this report, we describe the first case of Trisomy 13 diagnosed by FISH in Mali.

2. Case History

A 30‐day‐old male newborn was referred to our clinic for a polymalformative syndrome. He was the sixth child in the family, born to non‐consanguineous parents, with no reported history of genetic disease in the family. His mother and father were 40 and 46 years old, respectively. Family history was unremarkable, and the prenatal history indicated a decreased fetal movement at 7 months of pregnancy. The infant was delivered spontaneously at 38 weeks of gestation at a primary care reference center. He did not cry at birth and was admitted to the neonatal intensive care unit due to respiratory distress. He was subsequently discharged home and referred to our clinic at 30 days of age by his pediatrician.

3. Differential Diagnosis, Investigations, and Treatment

Thirty days after birth, the baby was brought to our clinic, where physical examination revealed postaxial polydactyly in the left hand, microtia, micrognathia, anophthalmia, and clubfoot (Figure 1). Cardiac and pulmonary examinations revealed a pronounced heart murmur accompanied by pericardial friction rub, as well as wheezes and rhonchi in both lungs. Laboratory investigation showed hyperleukocytosis with 13,960 leucocytes/mm³, thrombocytopenia with 146,000 platelets/mm³, and an elevated level of C‐reactive protein (30.1 mg/L). Abdominal ultrasound detected hydronephrosis. Finally, heart Doppler ultrasound identified a 5 mm ventricular septal defect.

FIGURE 1.

Family tree and phenotypic features of the patient. (a) Family's pedigree showing a non‐consanguineous marriage and a single affected individual, (b) postaxial polydactyly, (c) microtia of the right ear, (d) microtia of the right ear, (e) anophthalmia and micrognathia.

The definitive diagnosis of Trisomy 13 was established through molecular cytogenetic analysis. Peripheral blood samples were collected from the patient and cultured. After 72 h, chromosomes were harvested and analyzed using fluorescence in situ hybridization (FISH) with an RB1 probe from Agilent (Agilent, Canada). The FISH analysis revealed three copies of chromosome 13, as indicated by the RB1 signals in the q region of chromosome 13 and the nuclei (Figure 2), confirming the diagnosis of Trisomy 13.

FIGURE 2.

A representation of a metaphase and nuclei following FISH analysis. (a) A complete metaphase showing three distinct red signals from a probe targeting the RB1 loci on the q arm of three distinct chromosomes 13 (indicated by white arrows). (b) Two distinct nuclei, each displaying three red signals, indicating three copies of chromosome 13.

4. Outcome and Follow‐Up

The patient's condition worsened progressively, with deterioration attributed to cardiorespiratory failure, resulting in his passing at 40 days of age.

5. Discussion

In this study, we report a case of Patau syndrome diagnosed by a molecular cytogenetic technique in a Malian newborn. This syndrome encompasses a spectrum of congenital abnormalities affecting multiple organs with varying degrees of severity, often leading to premature mortality death [2, 5, 8, 9, 10]. Several factors have been implicated in the occurrence of Trisomy 13, including advanced maternal age [11, 12], as observed in our case. Clinically, our patient presented with anophthalmia and postaxial polydactyly, two components of the classical clinical triad. Additionally, the patient displayed bilateral microtia, micrognathia, and skeletal deformities in the lower limbs, underscoring that the classical triad is not consistently observed and that additional clinical features can be associated with the pathology [2, 10, 13]. While cystic dysplasia is the primary renal abnormality described in previous reports [14], hydronephrosis was the main renal finding in our case. The ventricular septal defect, commonly identified as the primary congenital heart defect in Trisomy 13, was the only cardiac abnormality observed in our case, consistent with findings reported in the literature [13]. Therapeutic interventions for Trisomy 13 patients with heart defects are extremely limited in Mali, and the lack of availability of surgical repair for ventricular septal defects inevitably leads to a fatal outcome. Unfortunately, the patient passed away 10 days after diagnosis, at just 40 days of age, highlighting the trend of mortality of the disease within the first few weeks of life [4, 15].

We conducted molecular cytogenetic analysis using FISH to confirm the diagnosis. To the best of our knowledge, this represents the first documented case of diagnosed Trisomy 13 by FISH in Mali and the second to be diagnosed cytogenetically [16]. While FISH analysis offers the advantage of rapidity and the ability to be performed on interphase cells, bypassing the need for cell culture and chromosome analysis, its availability is limited in Sub‐Saharan Africa. However, FISH on interphase nuclei does not detect most structural chromosomal rearrangements or mosaicism; therefore, it should be complemented by karyotyping or chromosomal microarray to ensure comprehensive evaluation and accurate genetic counseling. The application of cytogenetic techniques for prenatal testing to detect Trisomy 13 is rarely carried out in Sub‐Saharan Africa [17]. This deficiency in prenatal screening frequently results in delayed postnatal diagnoses for most cases, intensifying the challenge of managing a condition already burdened with a poor prognosis. While cytogenetic techniques for diagnosing chromosomal abnormalities are well‐established in other parts of the world [18, 19], they remain scarce in Sub‐Saharan Africa. In high‐resource settings, chromosomal microarray (CMA) and noninvasive prenatal testing (NIPT) are now preferred as first‐line diagnostic methods for detecting chromosomal abnormalities due to their higher sensitivity and broader detection capabilities [17]. CMA, in particular, provides a more comprehensive analysis by identifying copy number variations that FISH cannot detect, while NIPT allows for early, noninvasive risk assessment. However, these advanced techniques remain largely inaccessible in many parts of Sub‐Saharan Africa due to financial and infrastructural constraints. In this context, FISH offers a practical approach that can be implemented in resource‐limited countries like Mali, allowing for both prenatal and postnatal diagnosis and intervention options. Therefore, there is an urgent need to develop and enhance these diagnostic approaches in the region.

Our findings contribute to the expanding clinical and cytogenetic understanding of Trisomy 13 in Africa, highlighting the imperative to strengthen local capacities for early diagnosis and appropriate management of affected newborns.

Author Contributions

Alassane Baneye Maiga: conceptualization, investigation, writing – review and editing. Oumar Samassekou: conceptualization, formal analysis, methodology, supervision, writing – review and editing. Cheick Oumar Sidibé: investigation, methodology, writing – original draft. Oumou Traoré: investigation, writing – review and editing. Belco Maiga: investigation, writing – review and editing. Mahamadou Traoré: writing – review and editing. Cheick Oumar Guinto: writing – review and editing. Guida Landouré: funding acquisition, writing – review and editing.

Ethics Statement

This study was conducted in full compliance with the declaration of Helsinki, and the study protocol has been approved by the Institutional Ethics Committee of the Faculty of Medicine and Dentistry of the University of Sciences, Techniques and Technologies of Bamako, Mali. Written consent and assent forms were obtained from all participants before enrollment and sharing of data, including photographs.

Consent

Written informed consent for publication of this case report and any accompanying images was obtained from the patient's legal guardian. A copy of the written consent is available for review by the editor‐in‐chief of this journal upon request.

Conflicts of Interest

The authors declare no conflicts of interest.

Maiga A. B., Samassekou O., Sidibé C. O., et al., “Using the Fluorescence In Situ Hybridization in the Diagnosis of Trisomy 13 in a Male Newborn From Mali,” Clinical Case Reports 13, no. 10 (2025): e71093, 10.1002/ccr3.71093.

Data Availability Statement

Data that support the findings of this study are available from the corresponding author upon reasonable request.